Anyone has remind join my class the code is myzoo

Combined megan and kelly worked 60 hours.kelly worked twice as many hours as megan.how many hours did they each worked?

Twice the sum of a number and 4 is equal to three times the difference of the number and 7. find the number.

Astuntman jumping off a 20-m-high building is modeled by the equation h=20-5t^2, where t is the same in seconds. a high-speed camera is ready to film him between 15m and 10m above the ground. for which interval of time should the camera film him?